High voltage electrodes for the ignition system of internal combustion engines and method for making the same

Abstract

To increase service life and suppress interferences in high voltage electrodes for the ignition distributing system of internal combustion engines, the electrodes consist of molded and sintered mixture of 50-90% by weight iron powder and 50-10% by weight calcium silicide. Preferably, the electrode has tipstretched contact area of nonalloyed iron.

We claim: 
     
       1. High voltage electrode for the ignition stystem of internal combustion engines, comprising 50-90% by weight iron and 50-10% by weight calcium silicide. 
     
     
       2. High voltage electrode in accordance with claim 2, further comprising tungsten and/or molybdenum. 
     
     
       3. High voltage electrode in accordance with claim 2, comprising 0.5 to 2.0% by weight tungsten and/or molybdenum. 
     
     
       4. High voltage electrode for the ignition distributing system of internal combustion engines, consisting of calcium, silicon and iron. 
     
     
       5. High voltage electrode in accordance with claim 4, comprising a tipstretched contact area consisting of a ductile metal, preferably nonalloyed iron. 
     
     
       6. Method of making high voltage electrodes for the ignition system of internal combustion engines, comprising the steps of mixing iron powder and calcium silicide powder, adding a binder, granulating the mixture, filling the granulate into a mold and molding the same, evaporating the binder, and sintering the granulate under a protective gas. 
     
     
       7. Method as defined in claim 6 further comprising the step of mixing calcium wolfromate and/or sodium molybdate to the iron powder and calcium silicide powder. 
     
     
       8. Method as defined in claim 6, wherein particle size of the iron and calcium silicide powder is <0.2 mm, the mixture is granulated after adding 0.5-3% by weight organic binder, 0.2-2% by weight of a pulverized organic lubricant is added to the granulate and the granulate is molded in a mold under pressure of about 4000 bar, then the resulting blank is removed from the mold and heated to a temperature between 300° and 500° C. under a protective nitrogen-hydrogen gas mixture to evaporate binder and lubricant substances, and then sintered at a temperature between 900°-1200° C. 
     
     
       9. Method as defined in claim 6 wherein said mold is separated by a separating wall into two chambers having different depths, and further comprising the steps of filling iron powder into a deeper chamber and said granulate into the other chamber, then removing the separating wall and simultaneously molding contents of both chambers to the same level, removing the blank, heating the blank to a temperature of 300°-500° C. under a protective nitrogen-hydrogen gas mixture, and then sintering the blank at a temperature of 900°-1200° C. to produce an electrode having a tip stretched contact area of nonalloyed iron.